Final answer:
The relevant proportion is 605/1060.
Step-by-step explanation:
A proportion is a mathematical expression that states that two ratios or fractions are equal. The relevant proportion in this case is the proportion of US teens aged 13 to 17 who say they have made a new friend online. To calculate this proportion, we divide the number of teens who have made a new friend online (605) by the total number of teens surveyed (1060). Therefore, the relevant proportion is 605/1060.